Optical spectroscopy is emerging as an important modality for assessment of the biologic state of living tissues. Determination of the concentration of hemoglobin in biologic tissue has importance in determining blood flow, and in determination of the oxygen availability to cells within tissues, among other things. Variation in the optical scattering properties of tissue results in an unknown optical path length and makes quantifying chromophores in biological tissues difficult. Methods for accounting for the scattering coefficient directly, such as time-resolved or phase modulated spectroscopy, or indirectly, such as the use of the spectral absorption of water as an internal standard, are problematic in that they assume a constant scattering coefficient and rely on changes in the total heme chromophore signal (Hb+Mb) to determine changes in muscle perfusion, but provide little information on the resting conditions. The inability to distinguish the Hb and Mb signals means that the contributions of the intracellular (Mb) and vascular (Hb) compartments cannot be separated using traditional methods of analysis of optical spectra.